Organotin phenolates

ABSTRACT

ORGANOTIN COMPOUNDS OF THE FORMULA   (RMSN)A((R&#39;&#39;)X-,1-O(-)-,2-((R&#34;)Y-(PHENYLENE)-CO)-BENZENE)B   (R&#39;&#39;&#34;)C   PREPARED BY THE REACTION OF AN AROMATIC HYDROXY CARBONYL COMPOUND AND AN ORGANOTIN OXIDE OR ALKOXIDE MAY BE USED AS STABILIZERS FOR SYNTHETIC RESINS.

United States Patent U.S. Cl. 260--429.7 8 Claims ABSTRACT OF THEDISCLOSURE Organotin compounds of the formula prepared by the reactionof an aromatic hydroxy carbonyl compound and an organotin oxide oralkoxide may be used as stabilizers for synthetic resins.

This application is a division application of Ser. No. 646,465, filed onJune 16, 1967, and now abandoned, which divisional is acontinuation-in-part of US. application Ser. No. 567,823, filed July 26,1966, now US. Pat. No. 3,498,947.

This invention relates to novel organotin compounds, to the preparationof such compounds, and to synthetic resins stabilized with saidorganotin compounds.

It is known that certain organic compounds may be added as ultravioletlight absorbers to various synthetic resins which are susceptible todegradation by ultraviolet light.

Certain of these ultraviolet light absorbers now in common use, may becharacterized by unsatisfactory stabilizing ability because of thermaldecomposition, volatilization, and sublimation during the process ofproducing films, fibers, or other molded articles. These compounds havea further defect in that when they are added to synthetic resins, suchas polyvinyl chlorides, they may promote the heat-deterioration of suchresins, When the synthetic resins are processed at a temperature above200 C., for example, these defects become even more pronounced.

In addition, when these known stabilizers are added to fibers, which areto be washed or dry-cleaned, considerable discoloration due to thereaction of extremely small quantities of metal ion or cleaning materialwith the stabilizers may often be observed.

According to the present invention, these adverse effects may be reducedor eliminated by employing a new class of organotin compounds asstabilizers.

It is an object of this invention to provide novel organotin compoundsand methods of producing such compounds. A further object of thisinvention is to provide synthetic resins stabilized with one or more ofthese novel organotin compounds. Other objects will be apparent to thoseskilled-in-the-art from the following description.

In accordance with certain of its aspects, the method of this inventionfor stabilizing synthetic resins against the degrading effect ofultraviolet light comprises incorice porating into said resin aninhibiting amount of a compound having the following formula:

(1V): (R")y I: wherein:

(1) R is selected from the group consisting of an alkyl, cycloalkyl, andaryl;

(2) each of R and R" is independently selected from the group consistingof alkyl, alkoxy, hydroxyl, halogen, carboxyl, and benzoyl (in whichsaid hydroxyl and carboxyl groups may be attached to the tin atom viathe hydroxyl-oxygen atom by removal of the hydrogen atom from saidgroups);

(3) R is selected from the group consisting of hydroxyl; carboxylic acidwherein R* is hydrogen or hydrocarbon; mercaptan ZS wherein Z is analkyl group; monovalent mercapto ester formed by removal of the hydrogenatom from the mercaptan portion of the ester molecule; and monovalentmonoester maleate residues formed by removal of the hydrogen atom fromthe carboxyl of said maleate monoester,

(4) C is an integer 0 3,

(5) a, b, and m: is each an integer 1-3,

(6) x and y is each an integer 03,

(7) when C is 1 or 2, R may be the divalent oxygen atom, and

(8) each unsubstituted atom in said compound is bonded to a hydrogenatom.

Examples of suitable alkyl groups (R,R, and R") include methyl, ethyl,n-propyl, i-propyl, n-butyl, sec.-butyl, tert-butyl, n-amyl, i-amyl, aswell as isomeric hexyl, heptyl, actyl, nonyl, decyl, undecyl, anddodecyl groups. In addition, R may be a tridecyl, tetradecyl,pentadecyl, hexadecyl, heptadecyl, or octadecyl group. Substitutedalkyls including benzyl may be employed. When R is a cycloalkyl group, Rmay be a cycloalkyl group of from 3 to 12 carbon atoms such ascyclopropyl, cyclobutyl, cyclohexyl, cycloheptyl, 2-ethyl-cyclohexyl,3,4,5-trimethyl cyclopentyl, etc. Suitable alkoxy groups R and R)include methoxy, ethoxy, propoxy, butoxy, pentoxy, etc. represented bythe formula {-OC H )H wherein k is an integer from 1 to 12. Similarly,each R' may be a mercapto group of the formula: {-SC H )H wherein m isan integer from 1 to 18. Where R' is a mercapto acid ester residue, Rmay have the forumla:

S-X( 7O--(CkH2k)H wherein X is an alkylene, alkenylene, or alkylidenegroup of from 1 to 6 carbon atoms and k is an integer of from 1 to 12.When R is an aryl group, suitable aryl groups may include phenyl, tolyl,xylyl, and naphthyl.

Thus, the following are illustrative of the subclasses which may beincluded within Formula IA:

In accordance with certain aspects of this invention, organotincompounds included in Formula IA may be prepared by heating a compound(1) of the formula:

wherein R, R", x, and y are as defined above with (2) a tri-, di-, ormono-organotin oxide- (or alkoxide) in a suitable inert solvent mediumsuch as benzene, toluene, etc. Other compounds within the generalFormula IA may be prepared by heating compounds (1) and (2) in thepresence of a mercaptan (usually of from 1 to 18 carbon atoms), amercapto acid ester (usually of from 2 to 18 carbon atoms), or acarboxylic acid (usually of from 1 to 18 carbon atoms).

The novel organotin compounds of this invention may be colorless tolight yellow, crystalline or non-crystalline substances, depending uponthe R, R, R, and R'" radicals, and the value of a, b, c, m, x, and y inthe general Formula LA. The compounds may be soluble in those generalorganic solvents which have a boiling point in the range of 40 to 300C., e.g. aromatic hydrocarbons, alcohols, ethers, esters, ketones,petroleum hydrocarbon, etc. The low volatility of these organotincompounds make them especially useful as stabilizers in synthetic resinformulations which require heat or exposure to elevated temperatureduring use or during the processing of the synthetic resin material.

Specific examples of the organotin compounds which are within the scopeof this invention include, among others, the following:

CH O

I 0 ll 04110) 3511 C- (CnHOzSIl (3:0

5011 0 0 O CgHn hHoh H iHmsn These organotin ultraviolet light absorbersand stabilizers maybe combined with or incorporated into the syntheticresins in several ways. For instance, the organotin compounds or mixtureof compounds may be added to the syntheic resins prior topolymerization. After the addition of the organotin compound, theadmixture may be polymerized and molded into films, fibers, or otherarticles. Alternatively, the organotin compound may be added to thesynthetic resin together with other additives such as anotherstabilizer, an anti-oxidant, a coloring agent, a mold lubricant, etc. bymixers, e.g. a ribbon blender, a highspeed mixer, a stirring mixer, etc.after which the mixture may be molded into films, fibers, or otherarticles. In addition, films, fibers, or other articles may be treatedwith solutions, suspensions or emulsions of the organotin stabilizersand ultraviolet light absorbers to solutions, suspenspreading. It isalso possible to add the organotin stabilizers and ultraviolet lightabsorbers to solutions, suspensions, or emulsions of the syntheticresins.

The synthetic resins which may be stabilized by the method of thisinvention include ABS (Acrylonitrile- Butadiene-Styrene) resin,cellulose, acetal resin, fluoroplastics, acrylic resins, chlorinatedpolyethers, alkyd resins, amino resins, urethane resins, epoxy resins,polyamide resins, phenoxy resins, furan resins, phenol resins,polyimides, polycarbonates, polyesters, polyethylene, polypropylene,polystyrene, polyvinyl chlorides, synthetic rubbers, etc.

Only an inhibiting amount of organotin compound is required. Preferably,the amount of the organotin stabilizers and ultraviolet light absorbersto be employed in the process of this invention is in the range of about0.001 to 5% by weight based on the weight of the synthetic resins, whichwill vary depending upon the kind of molded articles and the manner inwhich the organotin compounds are added.

The organotin compounds of this invention are especially useful in theproduction of the synthetic resins when these resins are molded orpolymerized at a relatively high temperature. Often conventionalstabilizers and ultraviolet light absorbers actually stimulate thethermal decomposition of resins at temperatures above about C. Forexample, when R is the residue of mercaptan {-SC H JH; m is an integerof from 1 to 18], mercapto acid ester (such as wherein X is in analkylene, alkenylene, or alkylidene group of from 1 to 6 carbon atomsand k is an integer of from 1 to 12, carboxylic acid or monoestermaleate in general Formula IA, the organotin stabilizers of theinvention can also impart resistance to heat to synthetic resins whichare susceptible to the effects of thermal oxidation, e.g. ABS resins,chlorine-containing resins, polyolefins, etc.

The following examples are submitted for the purpose of illustrationonly and are not to be construed as limiting the scope of the inventionin any way.

In the examples a series of tests were carried out comparing the effectsof various organotin compounds according to the following procedure: Ablack board (which was set at an angle of 45 on the south) was linedwith test specimens, and exposed to sunlight and weathering outdoors.The specimens were then checked for a change (usually a decrease) ofimpact strength (Du Pont Type Impact Machine), discoloration, or degreeof cracking. All specimens were given the same exposure and all partsare by weight unless otherwise indicated. The volatility of eachorganotin compound was compared with the volatility of the correspondingbenzophenone compound.

EXAMPLE 1 One-tenth mole of 2,2 '-dihydroxy-benzophenone (A) was reactedwith one-tenth mole of trioctyltin methoxide in 200 cubic centimeters oftoluene under reflux conditions for 6 hours. The solvent was thendistilled off under reduced pressure to give a compound (B) of theformula:

Five-tenths gram of the organotin compound (B) was added to 100 grams ofstyrene, the mixture was polymerized by heating at 100 C. for 2 days,and a sheet was made from the polymer thus obtained. The degree ofdiscoloration (as measured by the increase of yellow color of the sheet)was about of that of the control sheet which was made by the sameprocedure as above, but contained no ultraviolet light absorbers.

EXAMPLE 2 Two-tenths mole of 2 hydroxy 4-methoxy benzophenone (C) wasreacted with mole of bis-(tributyltin)-oxide in 200 cc. of benzene underreflux conditions for 6 hours. The benzene was then distilled olf underreduced pressure to give a compound (D) of the formula:

The compounds (C) and (D) were tested for volatility by the sameprocedure as in Example 1. The percent by weight of each compound whichwas lost was as follows: (C), 8.7%; (D), only 1.6%.

A film of polyethylene glycol terephthalate having a thickness of 0.05millimeter was immersed in an acetone solution containing 2% by weightof organotin compound (D) at 10 C. for 3.0 seconds, and the impregnatedfilm was then dried at 180 C. for 30 seconds. The treated film had alife of more than three times as long as untreated film when both wereexposed to ultraviolet light for the same length of time.

EXAMPLE 3 One-tenth mole of 2,2. dihydroxy-4-octoxy benzophenone ('E)was reacted with mole of diamyltin oxide in 200 cubic centimeters oftoluene under reflux conditions for 6 hours. The toluene was thendistilled off under reduced pressure to give a compound (F) of theformula:

I O 03H" The compounds (E) and (F) were tested for volatility by thesame procedure as in Example 1 giving the following percents by weightof each compound which was lost: (E), 4.2%; (F), only 0.9%.

100 milligrams of benzoyl peroxide and 0.5 gram of the organotincompound (F) were mixed together in 400 cubic centimeters of methylmethacrylate and the solution was polymerized and molded into hardplates of 2 mm. thickness. The brittleness on exposure to ultravioletlight (denoted as impact value) of the plate containing organotincompound (F) was only of that of a plate prepared by the same procedureas above but not containing any ultraviolet light absorbers.

EXAMPLE 4 One-tenth mole of 2-hydroxy-4-octoxy benzophenone (G) wasreacted with mole of dibutyltin oxide and mole of dodecyl mercaptan in200 cubic centimeters of benzene under reflux conditions for 5 hours.The benzene was then distilled ofl under reduced pressure to give acompound (H) of the formula:

(C4Hn) 2811 using a similar technique, a compound (I) of the formula:

was prepared from A mole of 2-hydroxy-4-octoxy benzophenone (G) and Vmole of dibutyltin oxide.

The compound (G), (H), and (I) were tested for volatility by the sameprocedure as in Example 1 and gave the following results (percent byweight of each compound lost): (G), 3.2%; (H), only 0.7%; (I), only0.5%.

Two-tenths part by weight of each of the compounds (H) and (I) was addedto separate samples of 2,000 parts of 5% polyvinyl chloride solution inmethylnaphthalene, and the solution was spread out on a glass plate. Themethylnaphthalene was then stripped off from said glass plate underreduced pressure at 180 C. for 10 minutes leaving a colorless,transparent thin film of polyvinyl chloride. This film was notdiscolored after exposure to sunlight for 12 months.

For comparison purposes, a film without either (H) or (I) compounds, anda film with 0.2 part of the compound (G) were made by the same procedureas above. The initial colors of the two films were yellow. Both filmsturned brown after exposure to sunlight for 6 months in summer.

From these tests, it was concluded that the organotin compound (H) hadextremely low volatility and furthermore, that it rendered the polyvinylchloride stable not only to light, but also to heat.

EXAMPLE 5 Bu Sn I 0 II ....C 013300 Q The compounds (C) and (J) weretested for volatility by the same procedure as in Example 1 and gave thefollowing results (percent by weight of each compound lost): (C), 8.7%;(J), 2.0%.

Three parts of dibutyltin-bis-(benzyl maleate) as a stabilizer, 1 partof dibutyltin dilaurate as a lubricant, 0.6 part of the compound (J),and 0.4 part of the compound (H) used in Example 4 were mixed togetherthoroughly with parts of vinyl chloride resin. The mixture was sheetedon a mixing mill heated at a surface temperature of C. The sheetobtained was colorless and trans parent, and gave no coloration afterexposure to the sunlight over a long period of 32 consecutive months.

For comparison purposes, a sheet was prepared of the same composition asabove, but not containing either of the compounds (I) or (H). Anothersheet was prepared containing 1 part of the compound 2-hydroxy-4-methoxybenzophenone (C) instead of either of the organotin compounds (J) or (H)in the same manner as above. The former was colorless and transparent,and was not discolored after exposure to the sunlight for 22 consecutivemonths, but the latter [containing compound (C)] was light yellow incolor, and turned brown after exposure to the sunlight for 12 months.From these results, it was concluded that 2-hydroxy-4-methoxybenzophenone was not a satisfactory ultraviolet light absorber in viewof the fact that this compound had actually accelerated the thermaldecomposition of the synthetic resin.

EXAMPLE 6 Two-tenths mole of 2-hydroxy-4-methoxy benzophenone (C) wasreaoted with mole of monobutyl stannoic acid and mole of dodecylmercaptan in 200 cubic centimeters of toluene under reflux conditionsfor 6 hours. The toluene was then distilled off under reduced pressureto give a compound (K) of the formula:

The compounds (C) and (K) were tested for volatility by the sameprocedure as in Example 1 and gave the following results (percent byweight of each compound lost): (C), 8.7%; (K), only 1.6%.

An amount of each of compounds (C) and (K) was added to separate samplesof acrylonitrile-butadienestyrene terpolymer resins to give aconcentration of 0.5 percent by weight of each compound based upon thetotal weight of the resin and the mixtures were injection molded intofiat plates. The plate containing the compound (C) was yellow in colorwhen formed, but the plate containing the organotin compound (K) waswhite in color. From these results it was concluded that the compound(C) accelerated the thermal decomposition of the ABS resin whereascompound (K) did not. The time required to reduce the impact strength ofthe plate with the organotin compound (K) by a factor of one-half bymeans of irradiation with ultraviolet light was 9 to 11 times as long asthat of the plate with the compound (C) as measured by Du Pont TypeImpact Machine.

EXAMPLE 7 Two-tenths mole of 2-hydroxy-4-octoxy benzophenone (C) wasreacted with mole of bis-tribenzyltin oxide in 600 cubic centimeters ofheptane under reflux conditions for 8 hours. The heptane was thendistilled off under reduced pressure to give a compound (M) of theformula:

(CaHaCHz) S nCsO- The compounds (C) and (M) were tested for volatilityby the same procedure as in Example 1 and gave the following results(percent by weight of compound lost); (G), 3.2%; (M), 0.6%.

A sample of polypropylene containing 0.1% by weight of a 2,6-di-tertiarybutyl-4-methyl phenol and 0.2% by weight of dilauryl thio-dipropionate,and another sample of polypropylene containing 0.3% by Weight of thecompound (M) were each melt extruded. The fibers obtained were purewhite in color in each case, whereas the fibers made from polypropylenecontaining 0.3% by weight of the compound 2-hydroxy-4-octoxybenzophenone (O) instead of the compound (M) was light yellow in color.These fibers were then washed with anionic and non-ionic surfactants anddried in the sun repeatedly. Only the fibers with the compound (G)became yellow in color after several washings and dryings. The timerequired for the percentage maximum elongation of the fibers with thecompound (M) to be reduced to one-half of the original value due toirradiation with ultraviolet light was 22 times as long as in case ofthe fibers without any ultraviolet light absorbers, and was 8 times aslong as in case of the fibers with the compound (G).

EXAMPLE 8 One-tenth mole of 2,2'-dihydroxy-4,4-dimethoxy benzophenone(N) was reacted with mole of monooctyltin oxide in 600 cc. of hexaneunder reflux for 4 hours. The hexane was then distilled off underreduced pressure to give a compound (0) of the formula:

The compounds (N) and (0) were tested for volatility by the sameprocedure as in Example 1 and gave the following results (percent byweight of compounds lost): (N), 4.6%; (O) 0.9%.

An amount of the compound O) sufiicient to give a 1.5 percent by weightconcentration was added to polyethylene, and the mixture was extrudedinto a film of 0.6 mm. thickness. For comparison purposes, an additionalfilm was prepared from polyethylene without any additives by the sametechnique. Both of the films were colorless. These films were exposed toultraviolet light until their impact strength was reduced by one-half ofthe original value in order to test them for resistance to degradationby ultraviolet light. The polyethylene film containing the organotincompound (0) had to be exposed to ultraviolet light 17 times as long asthe polyethylene film containing the compound (N) in order to reduce theimpact strength by a factor of one-half.

Although this invention has been illustrated by reference to specificexamples, numerous changes and modifications thereof which clearly fallwithin the scope of the invention will be apparent to thoseskilled-in-theart.

We claim:

1. A compound of the formula:

CaHn S n wherein (a) each of R, R, and R" is independently an alkylgroup of from l-18 carbon atoms and, (h) each of x and y is an integer0-3. 2. A compound of the formula:

wherein 7. A compound of the formula:

(a) R is an alkyl group having 1-18 carbon atoms, (b) each of R and R"is independently selected from the group consisting of alkyl and alkoxygroups having 1-18 carbon atoms and, 5 (0) each of x and y isindependently an integer 0-3.

CH 0- 3. A compound of the formula: i\

SGIZHZB o 0 O O R CH3O wherein each R is independently an alkyl grouphaving 8 Alcompound of the formula, 1-18 carbon atoms.

4. A compound of the formula:

OCH;

ll 0 (CaH17)sSn CBHHISD. 0:0

O-- OCH:

5. A compound of the formula:

(C4HO)3SII-*IO 0 -(HIM References Cited UNITED STATES PATENTS C11302,727,917 12/1955 Mack et a1 260-429] 6 A d f h f 1 2,773,903 12/1956Hardy et a1 260--591 0 1 2,870,119 1/1959 Leistner et a1 260429.7X 0 Q3,129,236 4/ 1964 Weissenberger 260-429.7

JAMES E. POER, Primary Examiner s 11)2 C=O W. F. W. BELLAMY, AssistantExaminer U.S. C1. X.R.

4o OCBH" 26045.75

